Chair back adjusting mechanism



Nov. 15, 1966 R. H. DE GASTON CHAIR BACK ADJUSTING MECHANISM OriginalFiled March 30, 1964 INVENTOR. 5,4001 H. a'e GA57'0/v United StatesPatent 3 Claims. (Cl. 297-374) This application is a continuation of mypending application, Serial No. 355,546, filed March 30, 1964, titledChair Reclining Mechanisms, now abandoned.

This invention relates to chair construction and deals more specificallywith mechanism for adjusting the angle of a chair back relative to chairseat to a chosen position.

An object of the present invention is to provide improved and simplifiedmeans for adjusting the angle of a chair back that eliminates ratchetmechanisms, such as used in existing chair structures.

Another object of the invention is to provide mechanism, as abovecharacterized, that is easily adjusted without the need for tools of anysort whatever.

A further object of the invention is to provide chair back adjustingmechanism that may be adjusted to an infinite number of angularlyinclined positions.

A still further object of the invention is to provide mechanism, asabove characterized, that has long useful life, in that wear is minimal.

This invention also has for its objects to provide such means that arepositive in operation, convenient in use, easily installed in a workingposition and easily disconnected therefrom, economical of manufacture,relatively simple, and of general superiority and serviceability.

The above objects are realized in a chair back adjusting mechanism thathas a back that is pivotally mounted on the seat of the chair, saidmount comprising a drum or cylinder that is freely rotational on ahorizontal axis that extends in a transverse direction at the rear ofsaid seat and is fixedly carried by the chair back, and a helical springhaving several convolutions tightly wound on said drum with one endfixedly connected to the seat back and the other end being rearwardlyand then upwardly extended to form a handle. Said spring is wound in adirection that causes it to tightly frictionally grip the fixed drum tohold the seat back non-movable against forces tending to move it in abackward direction, as when a person on the chair leans against saidback. Said chair back retains its position due to the fact that thespring coils cannot turn over the surface of said drum, as explained,due to their frictional engagement with the drum.

Any enlargement of the coils of the spring will enable the back to beangularly adjusted, in either direction, on the drum axis. To this end,the handle end of the spring is flexed in a rearward and downwarddirection to cause the spring coils to become enlarged. Now, the backmay be adjusted to a desired angle of slope and, upon release of saidhandle, the spring coils automatically and instantly grip the drum tohold this adjusted position.

The invention also comprises novel details of construction and novelcombinations and .arrangements of parts, which will more fully appear inthe course of the following description and which is based on theaccompanying drawing. However, :said drawing merely shows, and thefollowing description merely describes, one embodiment of the presentinvention, which is given by way of illustration or example only.

In the drawing, like reference characters designate similar parts in theseveral views.

FIG. 1 is a side elevational view of a chair having a pivotallyadjustable back and provided with the adjusting means of the presentinvention.

FIG. 2 is an enlarged side elevational view of the present backadjusting means.

FIG. 3 is a front view as seen in the direction of the arrow 3 of FIG.2.

FIG. 4 is a further enlarged plan sectional view of the present means astaken on the line 44 of FIG. 2.

FIG. 1 shows a chair that has a seat 5 that is mounted on a conventionalpedestal 6, and is provided with a back 7.

The present chair back adjusting mechanism comprises generally amounting bracket 8 that is affixed to the seat 5, preferably to thebottom face thereof, a drum or cylinder 9 fixedly carried by saidbracket, an axle 10 extending through the horizontal axis of said drumand carried by the bracket 8, a coil spring 11 wound tightly around saiddrum 9 with one end 12 extending rearwardly and then upwardly, and asecond bracket 13 to which the chair back 7 is aflixed and rotationallymounted on the axle 10, the other end 14 of the spring 11 being anchoredto the bracket 13.

The bracket 8 has a mounting plate 15 and a hanger bar 16 extendingdownwardly from said plate at one side thereof.

The drum 9 is shown as a smooth faced cylinder and extends laterallyfrom the hanger bar 16.

The axle 10 isshown as a bolt that by means of a nut or threaded collar17 is affixecl to the hanger bar. The same has a headed end that extendsbeyond the drum 9.

The spring 11 is a conventional coil spring that has its convolutions ofa size to frictionally grip the surface of the drum 9. The samecomprises several turns with the end of one outer turn or convolutionforming the end 12 which has a knob 18 at its upper end 'by means ofwhich the same comprises a handle.

The bracket 13 comprises a plate 19' to which the chair back 7 isaifixed and a forwardly extending plate 20 through a hole in which thementioned head end of the axle 10 extends. The end 14 of the convolutionon the opposite end of the spring 11 is anchored in said plate 20 bybeing extended laterally through a hole 21 in said plate.

Since the spring 11 is wound so as to tend to tighten around the drum 9when the spring end 14 is pulled as by a rearward force on the chairback 7, said back 7 will remain in any angular position to which it hasbeen adjusted. By flexing the handle end 12 of spring 9 in a rearwarddirection, the coils of the spring 9 are infinitestimally enlarged, suchenlargement effecting sufiicient release of the fixed drum, enabling theback 7 to be adjusted as desired while said handle is retained flexed,as described. Then, upon release of the handle 12, the spring 9instantly grips the drum to hold the adjustment.

It will be evident that the spring 9 frictionally clutches the drum.Therefore, the mechanism constitutes a friction clutch that enablesminute adjustment of the chair to be made.

While the foregoing has illustrated and described what is nowcontemplated to be the best mode of carrying out the invention, theconstruction is, of course, subject to modification without departingfrom the spirit and scope of the invention. Therefore, it is not desiredto restrict the invention to the particular form of constructionillustrated and described, but to cover all modifications that may fallwithin the scope of the appended claims.

Having thus described this invention, what is claimed and desired to besecured by Letters Patent is:

1. Adjusting mechanism for a chair having a seat and a separate back,said mechanism comprising:

3 4 (a) a drum fixedly secured to the seat and on a horia second bracketis connected to the seat, and the drum zontal axis transverse to theseat, is afiixed to the latter bracket.- (b) a bracket carrying the,chair back and freely piv- 3. Adjusting mechanism according to claim 2in which otally mounted on said axis, the mentioned axis comprises anaxle extending from the (c) a coil spring wound with its coils infriction tight 5 latter bracket .and through the drum.

engagement with the cylindrical surface of the drum,

((1) one end of said spring affixed to the mentioned References Cit d bth E i bracket ad'acent to the spring coils, and

(e) the oppc usite end being extended first rearwardly UNITED STATESPATENTS beneath the chair back and then upwardly and rear- 10 376,8861/1888 Holden 297292 wardly behind the chair back, to form a handl that,1,011,713 12/ 1911 Bainer 297304 when flexed in a rearward direction tocau e en- 1,856,534 5/1932 Boery 297374 largelment of the convolutionsof the spring, causes 3, 04,130 9 19 .3 Martens 297-355 release of thefriction grip between the spring and the drum, thereby releasing theback for adjustment 15 FRANK SHERRY, Primary Emmi-net to a desired angleon the mentioned axis.

2. Adjusting mechanism according to claim 1 in which R. B. FARLEY, G. O.FINCH, Assistant Examiners.

1. ADJUSTING MECHANISM FOR A CHAIR HAVING A SEAT AND A SEPARATE BACK,SAID MECHANISM COMPRISING: (A) A DRUM FIXEDLY SECURED TO THE SEAT AND TOA HORIZONTAL AXIS TRANSVERSE TO THE SEAT, (B) A BRACKET CARRYING THECHAIR BACK AND FREELY PIVOTALLY MOUNTED ON SAID AXIS, (C) A COIL SPRINGWOUND WITH ITS COIL IN FRICTION TIGHT ENGAGEMENT WITH THE CYLINDRICALSURFACE ON THE DRUM, (D) ONE END OF SAID SPRING AFFIXED TO THE MENTIONEDBRACKET ADJACENT TO THE SPRING COILS, AND (E) THE OPPOSITE END BEINGEXTENDED FIRST REARWARDLY BENEATH THE CHAIR BACK AND THEN UPWARDLY ANDREARWARDLY BEHIND THE CHAIR BACK, TO FORM A HANDLE THAT, WHEN FLEXED INA REARWARD DIRECTION TO CAUSE ENLARGEMENT OF THE CONVOLUTION OF THESPRING, CAUSES RELEASE OF THE FRICTION GRIP BETWEEN THE SPRING AND THEDRUM, THEREBY RELEASING THE BACK FOR ADJUSTMENT TO A DESIRED ANGLE ONTHE MENTIONED AXIS.